The present invention relates to electrical measurements and, in particular, to a high speed AC source.
Measuring the AC characteristics of a device under test (DUT) can be difficult. Stray capacitances at the output of the measurement system can become significant loads as the AC frequency increases and/or the pulse width of applied signals becomes narrow. Also, typically for a current measurement, a voltage is measured across a sense resistor in series with the DUT. This means that the voltage applied to the DUT itself is not the same as the voltage applied by the measurement system across the DUT and sense resistor. This is further complicated if the DUT exhibits rapid changes in impedance. For example, phase-change random-access memory (PRAM) and resistive random-access memory (RRAM), can rapidly change their impedance to represent digital data. These rapid impedance changes make it difficult to control voltage and current at the DUT.